Ceramic cutting tools availability during interrupted machining was solution at this article, in the concrete ceramic DISAL D320 from Czech producer Saint Gobain Advanced Ceramic Turnov. Experiments were provided at special fixture – interrupted cut simulator. This fixture was constructed at Department of Machining and Assembly. Monitored parameter was number of shocks to totally destruction. The goals of tests were contribute to bigger using of these cutting materials at machining, especially at interrupted machining

Cep, Robert

Ocenasova, Lenka

Sadilek, Marek

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Ceramic Cutting Tool Test with Interputted Cut Simulator

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III. Mezinárodní konference STROJÍRENSKÁ TECHNOLOGIE – PLZEŇ 2009 21. – 22. 1. 2009 Testování nástrojů z řezné keramiky na simulátoru přerušovaného řezu Ceramic Cutting Tool Test with Interputted Cut Simulator Robert CEP, Lenka OCENASOVA, Marek SADILEK Department of Machining and Assembly, Faculty of Mechanical Engineering VSB – TU Ostrava, 17. listopadu 15/2172, CZ 708 33, OSTRAVA, Czech Republic e-mail: robert.cep@vsb.cz, phone: +420 59 732 319 Abstract:  Ceramic cutting tools availability during interrupted machining was solution at this article, in the concrete ceramic DISAL D320 from Czech producer Saint Gobain Advanced Ceramic Turnov. Experiments were provided at special fixture – interrupted cut simulator. This fixture was constructed at Department of Machining and Assembly. Monitored parameter was number of shocks to totally destruction. The goals of tests were contribute to bigger using of these cutting materials at machining, especially at interrupted machining.   Key words: Cutting Tools, Cutting Wear, Interrupted Machining, Shocks  1. INTRODUCTION   For the highest machining achievement is critical choice of right cutting tool. Choice of material and cutting geometry simulate big part. Vibration generate in machining induce early ending of tool life. It may be for example poor tool holder stiffness or mistaken clamping [5].  Producers of ceramic cutting tools made during centuries big step ahead. Namely increasing tenacity at conservation of high fortress and hardness is advantage. Some producers of these materials advise cutting inserts for interrupted machining at present time [3].   2. CHOSEN CUTTING MATERIALS  Today, do not exist standardized vocabulary, like e.g. at sintered carbides or high-speed steel. Generally is accepting following graduation. There are two basic types of ceramics  [1, 4]:  Aluminum – Oxide based (Al2O3) o Pure o Mixed o Reinforced  Silicon – Nitride based (Si3N4)  Like cutting materials we chosen products of Czech producer – Saint Gobain Advanced Ceramics Turnov. Like representative of cutting inserts we chose material DISAL D320 (Al2O3+TiC). The producer characterize it’s product like ceramics while maintaining high hardness and toughness this type is also thermal shock resistance, thus allowing machining in partially interrupted cutting and also coolant is acceptable. Machining of chilled cast iron, hardened steel (up to 64 HRC), medium and fine milling are particularly good area of application.       III. Mezinárodní konference STROJÍRENSKÁ TECHNOLOGIE – PLZEŇ 2009 21. – 22. 1. 2009 3. USING FIXTURE – INTERRUPTED CUT SIMULATOR  And now to several experiment, which was provided at special fixture – interrupted cut simulator (fig. 1). It was constructed at our department (Department of Machining and Assembly) within solution of Czech Science Foundation. Main parts of this simulator are:  Fixture’s body  Work pieces  Exchangeable moldings  Clamping gussets  Safety circles with screws  Fixture assembling proceed by follow way. Body was clamping to lathe and then with clamping gussets workpieces. In the case of need bottom by exchangeable moldings and screw up safety circles. We are ready for tests now. Proportions of simulator are:  Total length 900 mm  Machining length (length of workpieces) 600 mm  Valve diameter 230 mm  Work piece’s profile 60x50 mm  Machining diameter differs from 270 to 235 during machining. An exchangeable molding (their variable thickness) is big advantage of this fixture. Diameter (cutting speed) is relatively constant during whole tests [2].                 fixture´s body workpieces exchangeable  moldings clamping gussets safety circles Fig. 1 Scheme of Interrupted Cut Simulator [1]  With regards to ISO 3685 (Tool Life Testing of Single Point Turning Tools), was choice follow cutting geometry:   cutting edge angle :   κr = 45°,    cutting edge inclination :  λs = - 6°,  III. Mezinárodní konference STROJÍRENSKÁ TECHNOLOGIE – PLZEŇ 2009 21. – 22. 1. 2009  rake angle :    γo = - 6°,    clearance angle :   αo = 6°,  included angle :   εr = 90°,    Before first measuring at new work pieces is necessary machining first chip. This chip have not constant cross cut and could be deface whole metering (fig. 2). This is small disadvantage of this fixture.         Testing Cutting Tool   Fig. 2 Regulation of New Work Pieces [1]  That was achieved with this type tool holder (CSRNR 25x25M12 – K) and with this kind of cutting insert (SNGN 120716 T02020). Material of workpieces were 12 050  (Rm = 725 MPa).  4. MONITORING OF SHOCK´S NUMBERS  Parameter, which was monitoring is number of shocks to cutting tool destruction. Shock’s number was determinate from follow equation:  flR⋅= 4, where:        (1) R – number of shocks [--] l – cutting length [mm] f – feed [mm].  We monitored number of shock to total destruction of insert. Approaching destruction was demonstrated change of tone (strong) during machining. We were constant cutting parameters – cutting depth and revolutions (let us say cutting speed) and changed cutting feed from 0,16 mm to 0,31 mm (table 1 and table 2). We monitored surface roughness parameters Ra and Rz too. Values at tables are arithmetical mean of three measuring. After evaluation of follow tables, we obtain follow graphs (fig. 3 to fig. 5).       III. Mezinárodní konference STROJÍRENSKÁ TECHNOLOGIE – PLZEŇ 2009 21. – 22. 1. 2009  table 1. Measured values for cutting speed 408 m.min-1 vc = 408 m.min-1, ap = 1 mm f [mm] l [mm] Ra [μm] Rz [μm] R [-] 0,16 160 1,00 4,99 4000 0,2 163 1,02 5,05 3350 0,25 88 1,34 5,67 1400 0,31 105 1,71 6,07 1355    table 2. Measured values for cutting speed 580 m.min-1 vc = 580 m.min-1, ap = 1 mm f [mm] l [mm] Ra [μm] Rz [μm] R [-] 0,16 115 1,14 5,24 2875 0,2 115 1,01 5,03 2300 0,25 75 1,14 5,39 1200 0,31 45 1,4 5,68 581   Dependence of cutting feed to shock numbers (ap = 1 mm)01000200030004000500060000,1 0,15 0,2 0,25 0,3 0,35 0,4feed [mm]shock numbers [--]vc = 408 m.min-1 vc = 580 m.min-1 Fig. 3 Dependence of feed to shock numbers   We can generally tell, that with increasing cutting speed or feed, number of shocks decreasing. Graphical dependence of feed to numbers of shocks is at figure 3. Spline is  III. Mezinárodní konference STROJÍRENSKÁ TECHNOLOGIE – PLZEŇ 2009 21. – 22. 1. 2009 approximating like linear line. We can see that lines for both cutting speed decreasing almost parallel. Near of feed 0,35 mm will be impossible more machining. Dependence of cutting speed to shock numbers (ap = 1 mm)0500100015002000250030003500400045005000300 350 400 450 500 550 600 650cutting speed [m.min-1]shock numbers [--]f = 0,16 mm f = 0,2 mm f = 0,31 mm f = 0,25 mm Fig. 4 Dependence of cutting speed to shock numbers  We can tell that at lower feeds is number of shock higher at next figure 4 than at higher feeds. Line’s inclination is relatively parallel, except line at feed f = 0,25 mm. This departure can be caused by inclusion at workpieces or defect at cutting inserts. Approximation splines were linear lines.  Dependence of feed to surface roughness (ap = 1 mm)012345670 0,05 0,1 0,15 0,2 0,25 0,3 0,35 0,4feed [mm]surface roughness [ μm]Rz at 408 m.min-1 Rz at 580 m.min-1 Ra at 408 m.min-1 Ra at 580 m.min-1 Fig. 5 Dependence of feed to surface roughness   III. Mezinárodní konference STROJÍRENSKÁ TECHNOLOGIE – PLZEŇ 2009 21. – 22. 1. 2009   How we can see at figure 3, surface roughness is very similar at both cutting speeds. With in. CONCLUSIONS Cutting edge durability and cutting conditions optimizing are dependent at many paramer use of ceramic materials. Tests docum accurately result, must do more tests by higher cutting conditit department at diploma, dissertation and hat number 101/08EFERENCES [1] CEP, Robert. Ceramic Cutting Tool Tests at Interrupted Machining : dissertation [2]  In WORKSHOP [3] ation of Technological Processes (in Slovak) 1. ed. Prešov : [4] OLS – Materials, Development and [5] l  creasing feed surface roughness is decreasing too, but accruement is not expressive. This is valid for both parameter of roughness Ra and Rz. Approximating spline is exponential, but can be linear.   6 ters [4]. There are no easy determining exact areas. Every cutting process is unique. Submitted paper was dealing with problems of tool life tests of ceramics cutting tools at interrupted cut. Experiments were provided at fixture for along turning. This fixture was constructed at Department of Machining and Assembly. These tests purpose were contributed to higheented, than ceramics cutting tools are acceptable for interrupted cut. Roughness parameters Ra and Rz are adequate. For more objective and moreons, various workpieces materials and other ceramics cutting tool producers. Machine tool load and stiffness not allow higher cutting conditions. Especially machine tool stiffness is basic premise for measuring right and objective values.  Next test and result will provide and published abilitation thesis. Fixture simplified construction for along turning and facing turning is main target to future. These tests are very costlier and time consuming. Next tests are planning for steel 15 128 and for insert with aluminum oxide based DISAL D210.  This paper was solution in support by Czech Science Foundation, gran/P118 with name Ceramic Cutting Tool Tests at Interrupted Cut.  R thessis (in Czech). Ostrava : VŠB – TU Fakulta strojní. 2005. 101 p.  CEP, Robert. Ceramic Cutting Tools and their Application Areas. Faculty strojní 2005. Ostrava : VŠB – TU Ostrava, 2005, p. 79 + proceedings at CD. ISBN 80–248–0750–95. HATALA, Michal: SimulFVT TU, 2007. 85 p. ISBN 978-80-8073-756-6.  WHITNEY, E. Dow. CERAMICS CUTTING TOPerformance. Gainesville : Noyes Publications, 1994. 353 s. ISBN 0–8155–1355–0.  SANDVIK Coromant, Technical Editorial dept. Modern Metal Cutting – A PracticaHandbook. Tofters Tryckery AB, Sweden, 1994, 927 s. ISBN 91 – 972290 – 0 – 3.        ZPĚT 

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Ceramic Cutting Tool Test with Interputted Cut Simulator

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